Canyoneers almost swept to death by flash flood

A group of thrill seekers canyoneering in a US national park got more excitement than they hoped for when a raging flash flood threatened to sweep them to their deaths.

Eric Hanson, his brother Dave and his friends Eric and Ben were abseiling down a cliff in Utah's Zion National Park on August 25 when a sudden change in the weather nearly turned their day to tragedy, the St George Utah News reports.

"I underestimated nature and its ability to turn from tranquil beauty to a freight train of violent energy that destroys without mercy," Mr Hanson wrote on his blog.

A video of the harrowing incident shows the moment a light drizzle suddenly turned into a deadly torrent.

The footage shot by Mr Hanson shows water gushing down the sandstone cliff where his friend was poised to make his descent .

"I'm terrified that at any second I'm going to watch a wave of water pour off the rappel, carrying my friend with it," Mr Hanson wrote.

All four men manage to make it further down the cliff safely but then a new threat emerges as the rain intensifies.

With the water pelting down it is too dangerous to descend to the ground but the icy waters are rapidly inducing hypothermia, ruling out waiting around as an option.

After briefly deliberating the men decided to climb over a boulder that is partially shielding them from the flowing water, and attempted an exit using tree branches and other debris washed down the cliff by the water.

After a struggle to climb over the large rock with their energy drained from a day of hiking and the emotion of their near-death experience the men eventually made it over the boulder to safety.